There are 1.1 million persons living with HIV (PLWH) in the US, 60% of them smoke cigarettes, and 75% of these are interested in quitting. Almost none are currently accessing smoking cessation interventions designed to meet their specific needs and concerns. Cigarette smoking is responsible for 24% of deaths among PLWH, and 30% of non-AIDS defining malignancies. It is driving the alarming rise in cardiac events and lung cancers in this highly vulnerable population. The lack of access to proven, effective, culturally appropriate tobacco cessation services represents a health disparity of the first order. The psychosocial profile of the PLWH-smoker community, characterized by high rates of psychiatric comorbidity, drug and alcohol use, and low levels of social support, suggests that achieving high cessation rates will be a great challenge. Positively Smoke Free (PSF) is an intensive, multisession, group cessation program specifically developed for PLWH smokers. A pilot study of PSF yielded promising results. This proposal aims (1) to perform a definitive efficacy study of PSF by comparing 6-month biochemically confirmed abstinence rates in subjects randomized to PSF vs. standard care in a cohort of 450 PLWH smokers, (2) to determine the sociobehavioral moderators and mediators associated with successful cessation, and (3) to complete a careful cost analysis of PSF in order to estimate the incremental cost per quit associated program participation. If PSF is proven to be effective it will establish a new treatment option for PLWH smokers. Determination of moderators and mediators of program success will provide insight into the mode of action of the intervention and will help guide the development of additional treatment strategies in the future. Finally, the cost analyses will provide critical information abut the feasibility of program dissemination and implementation.